[0001] The present invention concerns polyarylene thioether compositions. Hereinafter, polyarylene
thioether is referred to as PATE and polyisobutylene is referred to as PIB.
[0002] PATE has been used in recent years as a crystalline thermoplastic resin excellent
in heat resistance, moldability, chemical resistance, flame retardancy and rigidity.
However, it has still insufficient toughness, impact resistance, etc. and improvements
therefor have strongly been wanted.
[0003] As a method of solving the problems on the toughness and impact resistance, several
attempts have been tried of melt-blending PATE with an impact modifier. However, since
the melt processing temperature for PATE is extremely high, conventional impact modifiers
such as natural rubber, SBR, NBR, isoprene rubber or modified product thereof are
liable to be thermally degraded upon melt-blending since they contain many thermally
degradable aliphatic double bonds in their molecule chain, and, accordingly, are not
suitable as the material for improving toughness and impact resistance of PATE.
[0004] Although an acrylic rubber type modifier has substantially no aliphatic double bonds
in its molecular chain, it is not satisfactory as an impact modifier to improve toughness
and impact resistance of PATE, since its ester bonds, etc. are also liable to be thermally
degraded upon melt-blending.
[0005] Modifiers which are heat resistant rubber such as fluoro rubber type and silicone
rubber type, show less thermal degradation upon melt-blending, but they have been
extremely uneconomical since they are expensive and show less improving effect when
added in a small amount.
[0006] Olefinic rubber type modifiers such as EPR show less thermal degradation since they
contain substantially no aliphatic double bonds and their costs are relatively inexpensive,
but their effect to improve toughness and impact resistance of PATE is low due to
an extremely poor compatibility with PATE. In addition, there has also been a problem
that the appearance of the molded product obtained by using them tends to be poor.
[0007] The present inventors have made an extensive study on the method of improving toughness
and impact resistance of PATE effectively and economically and, as a result, have
found that toughness and impact resistance of PATE can be improved remarkably by properly
adding PIB, which is an inexpensive rubbery high polymer, as a modifier. It has surprisingly
been found that the effect is particularly significant when PIB is used in combination
with a fibrous filler such as glass fibers. It is estimated that PIB acts not only
as an elastic absorbent for impact energy or stress but also acts as a sort of a coupling
agent at the interface between the fibrous filler and the PATE matrix (judged from
microscopic observation, etc.). Furthermore, it has also been found that humidity
proofness, etc. can also be improved as an additional effect. The present invention
has been accomplished based on these findings.
[0008] The object of the present invention is to provide a PATE composition capable of producing
a molded product having excellent toughness and impact resistance when fabricated.
[0009] Another object of this invention is to provide a composition of PATE containing a
novel impact modifier capable of withstanding the high processing temperature of PATE,
having good compatibility with PATE and relatively inexpensive.
[0010] The further object of the present invention is to provide a composition comprising
PATE, PIB, as an impact modifier for PATE, and fibrous filler and/or inorganic powdery
filler blended therewith, as well as a molded product prepared by fabricating said
composition.
[0011] The still further object of the present invention is to provide a molded product
with improved humidity proofness suitable to an application use such as packaging
materials.
BRIEF DESCRIPTION OF THE DRAWINGS:
[0012] Figures 1 and 2 are the pictures of scanning electron microscope of the flactured
test pieces. Each picture, P-1 and P-3 of Figure 1 and P-5 and P-9 of Figure 2, corresponds
to the test piece of Code Number of 1, 3, 5, or 9 of Table 1, respectively.
[0013] The PATE composition according to the present invention comprises the following ingredients
(A) and (B):
(A) PATE 100 parts by weight
(B) PIB 0.3 - 70 parts by weight
[0014] Another PATE composition according to the present invention comprises the following
ingredients (A), (B) and (C):
(A) PATE 100 parts by weight
(B) PIB 0.3 - 70 parts by weight
(C) Filler up to 400 parts by weight based on 100 parts by weight of (A) + (B)
[0015] Furthermore, the molded product according to the present invention comprises a PATE
composition comprising the following ingredients (A) and (B).
(A) PATE 100 parts by weight
(B) PIB 0.3 - 70 parts by weight
[0016] Further, another molded product according to the present invention comprises a PATE
composition comprising the following ingredients (A), (B) and (C):
(A) PATE 100 parts by weight
(B) PIB 0.3 - 70 parts by weight
(C) Filler up to 400 parts by weight based on 100 parts by weight of (A) + (B)
[0017] Regarding the first PATE composition and the composition for the molded products
described above, the expression : "comprising the ingredients (A) and (B)" means that
it includes, in addition to the composition consisting only of the ingredients (A)
and (B), those compositions further containing various kinds of auxiliary materials
customarily used in the usual thermoplastic resin compositions, for instance, various
types of stabilizers, releasing agents, flame retarding agent, antistatic agents,
antioxidants, antirust agent, coupling agents, lubricants, pigments, foaming agents
and other auxiliaries, as well as synthetic resins and elastomers.
[0018] The second PATE composition and the composition for the molded product correspond
to a composition containing fibrous filler and/or inorganic powdery filler as one
of such auxiliary materials.
PATE
[0019] Generally, PATE means a polymer having a repeating unit of (̵ Ar-S T (Ar : arylene
group) as the constituent element and PATE used in the present invention has p-phenylene
group as arylene group as the main constituent. The expression "as the main constituent"
in the present invention means that the repeating unit of

is contained not less than 60 mol% and, preferably, not less than 75 mol% of the total
repeating unit of (̵ Ar-S)̵.
[0020] Those having p-phenylene group as the main constituent of arylene group are preferred
in view of the physical properties such as heat resistance, moldability and mechanical
properties.
[0021] Arylene groups other than p-phenylene group as the main constituent usable herein
can include, for example, m-phenylene group

o-phenylene group

alkyl-substituted phenylene group

(in which R is an alkyl group, preferably, a lower alkyl group and n is an integer
of 1 to 4), p,p'-diphenylene-sulfone group

p,p'-biphenylene group

p,p'-diphenylene ether group

, p,p'-diphenylene carbonyl group

naphthalene group

etc.
[0022] From the view point of processability, copolymer containing different kind of repeating
units are excellent in most cases than homopolymers consisting only of the repeating
units of

[0023] As the copolymer, a copolymer of

is preferred. Particularly, those containing the respective repeating units in a block
form is preferred to those containing them in a random form (for example, as described
in EPC Application Laying Open No. 166451), because use of the block-copolymer is
remarkably excellent in physical properties (heat resistance, mechanical property,
etc.) although they are substantially equal in the processability. 5 to 40 mol% of
repeating unit of

namely, 95 to 60 molO/o of repeating unit of

in the block copolymer is preferable. Particularly, 10 to 25 mol% of repeating unit
of

is more preferable.
[0024] As the PATE in the present invention, those having substantially linear structure
are preferred in respect to the processability and the physical property. However,
crosslinked products obtained by using a small amount of a crosslinking agent (for
example, 1,2,4-trihalobenzene) upon polymerization within a range not impairing the
processability and the physical property may also be used.
[0025] Although cured PATEs can be used as a polymer in the present invention, uncured PATEs
are more preferable.
[0026] Since cured PATEs contain many branched or crosslinked structures, its use involves
various problems in respect to physical properties of the molded products and a processability
of the composition, such a poor mechanical strength, severe discoloration and low
heat stability upon melt processing.
[0027] PATE with the melting point higher than 250° C is preferable for the present invention.
If the melting point is lower than 250°C, the major feature as a heat resistant polymer
is impaired.
[0028] The preferable PATE for the present invention can be manufactured economically by
the process described in US Patent No. 4645826 filed by the present inventors. In
addition a method described in U.S. Patent No. 3,919,177 in which a polymerization
aid such as a carboxylic acid salt is added in a large amount to obtain a high molecular
weight PATE can also be used. However, the latter method is disadvantageous from an
economical point of view.
Modifier
[0029] The modifier to be used in the present invention to improve toughness and impact
resistance of PATE is PIB. In the present invention, "PIB" means a polymer having
the repeating unit of -(̵CH2-C(CH
3)
2)̵ as the main constituent, which may have a crosslinked structure or not.
[0030] PIB usable in the present invention can be the one containing repeating unit of (̵CH
2-C(CH
3))̵ by not less than 60 moI%, preferably, not less than 80 mol% and, particularly
preferably, not less than 90 mol%. However, those containing a considerable amount
of aliphatic double bonds in the molecular chain are not preferred since they are
liable to cause thermal degradation upon melt-blending with PATE. The permissible
content of the aliphatic double bond of

(in which R
1, R
2 = H or a hydrocarbon group) in the polymer is not more than 5 mol0lo, preferably,
not more than 2 mol% and, particularly preferably, not more than 1 mol%.
[0031] The molecular weight of the PIB as the modifier in the present invention has molecular
weight, of 5,000 to 500,000 and, preferably, 10,000 to 400,000. If the molecular weight
is less than 5,000, the effect of improving the impact resistance may possibly become
insufficient, whereas if it exceeds 500,000, it becomes difficult to disperse uniformly
in PATE. Either way is not desirable.
[0032] The molecular weight as described above is determined by the conventional method
based on the solution viscosity using diisobutylene (measuring temperature: 40°C).
[0033] The amount of PIB mixed in PATE is within a range of 0.3 to 70 parts by weight, preferably,
1 to 50 parts by weight and, particularly preferably, 3 to 30 parts by weight based
on 100 parts by weight of PATE. If it is less than 0.3 part by weight, the effect
of improving toughness and impact resistance may possibly become insufficient, whereas
if it exceeds 70 parts by weight, physical properties of the composition such as heat
resistance, flame retardancy and rigidity may significantly be degraded, which are
not desirable.
[0034] The PIB used in the present invention is preferably stabilized by an addition of
a heat stabilizer. As a heat stabilizer, those heat stabilizers such as hindered phenols,
phosphite esters, etc. can be used and, among all, hindered phenols, particularly,
having not less than 180 of molecular weight are preferred. If the molecular weight
is lower than the above, the evaporating ratio upon melt processing becomes unpreferably
too high.
[0035] The amount of the heat stabilizer used based on 100 parts by weight of the PIB is
0.1 to 10 parts by weight and, preferably, 0.2 to 5 parts by weight. The stabilizing
effect is insufficient if the amount is less than 0.1 parts by weight, whereas economical
disadvantage is resulted if it exceeds 10 parts by weight.
[0036] While the heat stabilizer may be added upon blending of PIB and PATE or the filler,
it is particularly preferable to add the stabilizer to the PIB prior to the blending
with PATE or the filler thereby stabilizing the PIB, in respect to the reliability
and the high efficiency.
Filler
[0037] The PATE composition according to the present invention may be formed, as it is,
into a molded product of excellent toughness and impact resistance by various melt
processing methods. However, it is preferred to use the composition in combination
with various kind of fillers. As the filler, there can be mentioned fibrous filler,
inorganic powdery filler and various kinds of synthetic resins and elastomers.
(i) Fibrous filler
[0038] These fibers such as of glass, carbon, graphite, silicon carbide, silica, alumina,
zirconia, potassium titanate, calcium sulfate, calcium silicate and aramide, as well
as natural fibers such as wollastonite and a mixture thereof are usable for the present
invention.
(ii) Inorganic powdery filler
[0039] These powders such as of talc, mica, kaolin, clay, diatomaceous earth, magnesium
phosphate, magnesium carbonate, calcium carbonate, calcium silicate, calcium sulfate,
silicon oxide, aluminum oxide, titanium oxide, chromium oxide, iron oxide, copper
oxide, zinc oxide, carbon, graphite, boron fluoride, molybdenum disulfide, silicon
and a mixture thereof, can be used for the present invention.
(iii) Synthetic resin and elastomer
[0040] These synthetic resins such as polyolefin, polyester, polyamide, polyimide, polyether
imide, polycarbonate, polyphenylene ether, polysulfone, polyether sulfone, polyether
ether ketone, polyether ketone, polyarylene, polyacetal, polyethylene tetrafluoride,
polyethylene difluoride, polystyrene, ABS, epoxy resin, silicone resin, phenol resin
and urethane resin, or elastomers such as polyolefinic rubber, fluoro rubber and silicone
rubber, are usable for the present invention.
[0041] The fibrous fillers exhibit particularly remarkable effect to improve toughness and
impact resistance of PATE by a coupling agent-like effect with PIB. The amount of
the fibrous filler used is preferably within a range up to 200 parts by weight based
on 100 parts by weight of a PATE/PIB composition ((A) + (B)).
[0042] The amount of the filler used is preferably within a range up to 400 parts by weight
based on 100 parts by weight of the PATE/PIB composition ((A) + (B)). If it exceeds
400 parts by weight, it is not preferable either because the melt processing may possibly
become difficult.
[0043] In the case of using a mixture of the fibrous filler and the inorganic powdery filler,
the difficulty or easiness of melt processing of the composition containing the mixed
filler is varied and the effect of the addition is also varied depending on the mixing
ratio of both fillers even if the same amount of the mixture is added. Thus it is
necessary to determine the adding amount of the mixture as a filler depending on the
cases on the condition that the melt processing can be performed normally.
[0044] The synthetic resin and the elastomer should be blended in such an amount as not
undesirably impairing the property of the PATE composition as the resin according
to the present invention. Accordingly, it is generally preferred that the their blending
amount is not more than the total amount of (A) + (B).
[0045] In addition to these fillers, a small amount of auxiliaries such as antioxidant,
heat stabilizer, light stabilizer, antirust agent, coupling agent, releasing agent,
lubricants, pigments, flame retarding agent, foaming agent and antistatic agent can
be added.
Preparation of The Composition
[0046] Since PATE is less soluble to usual solvents, the blending of PATE with PIB, other
fillers and auxiliaries is preferably performed by a melt kneading process using an
extruder or the like upon preparing the composition.
[0047] PIB can be blended by a dry process in which PIB is kneaded by itself in a pulverized
or finely chopped form and it can be also blended by a wet process in which PIB is
dissolved once in an organic solvent to make a solution, then mixed with PATE, removed
the solvent and then subjected to melt kneading.
[0048] The typical PATE composition of the present invention is the one which resin component,
that is, total of (A), (B), a synthetic resin and an elastomer, is in a coherent state
via a molten state.
Molded Product
[0049] The PATE composition according to the present invention can provide a molded product
of tough and high impact resistant by way of injection molding, extrusion molding,
compression molding, blow molding, etc. It can be used for various molded products
such as encapsulated molding product, various kinds of molded articles, or sheets,
films, plates, pipes, rods, profiles, bottles, etc.
Experimental Example
Synthesis Experimental Example 1:
[0050] Into a titanium-lined autoclave, 423.2 kg of hydrous sodium sulfide (solid content,
46.13 o/o) and 927 kg of N-methyl-pyrrolidone (hereinafter referred to as NMP) were
charged and temperature was elevated to about 203°C, to distill out 167 kg of water.
65.4 kg of NMP was further added (total water amount/NMP = 3.5 mol/kg).
[0051] Then, 365.0 kg of p-dichlorobenzene was charged (total arylene group/NMP = 2.5 mol/kg).
[0052] After reacting at 220°C for 5 hours, 92.5 kg of water was further added (total water
amount/NMP = 8.75 mol/kg). Then, the content was polymerized at 265°C for 0.75 hour
and at 254°C for 4 hours.
[0053] The reaction mixture was sieved through a 0.1 mm mesh screen and only the granular
polymer was separated and washed with acetone and then with water to obtain a washed
polymer.
[0054] The washed polymer was immersed in an aqueous 2% NH
4Cl solution, treated at 40°C for 30 minutes, washed with water and dried at 80° C
under a reduced pressure to obtain a polymer A. The melt viscosity of the polymer
A (temperature = 310°C, sharing rate = 200 sec-
1) was 1600 poise.
Synthesis Experimental Example 2:
[0055] Into a titanium-lined autoclave, 372.6 kg of hydrous sodium sulfide (solid content,
46.09 %) and 1035 kg of NMP were charged and temperature was elevated to about 203°C,
to distill out 145.4 kg of water. 2.9 kg of water and 34.8 kg of NMP were further
added (total water amount/NMP = 3.0 mol/kg). Then, 290.0 kg of p-dichlorobenzene was
charged (total arylene group/NMP = 2.26 mol/kg).
[0056] After reacting at 210°C for 5 hours and 220°C for 3 hours, 77.1 kg of water was further
added (total water amount/NMP = 7.0 mol/kg). Then, the contents were polymerized at
258°C for 1.5 hours.
[0057] The reaction mixture was sieved through a 0.1 mm mesh screen and only the granular
polymer was separated, washed with acetone and then with water to obtain a washed
polymer.
[0058] The washed polymer was immersed in an aqueous 2
o/o NH
4CI solution, treated at 40° C for 30 minutes, washed with water and dried at 80°C
under a reduced pressure to obtain a polymer B. The melt viscosity of the polymer
B (temperature = 310°C, sharing rate = 10000 sec-
1) was 35 poise.
Example 1
[0059] As the modifier, the followings were used:
(1) SBR type rubber ("TOUGHPRENE A", registered trademark of the product manufactured
by Asahi Kasei Kogyo Co.)
(2) NBR type rubber ("ZETPOLE 2020", registered trademark of the product manufactured
by Nihon Zeon Co.)
(3) Olefinic type rubber ("TAFMER-A", registered trademark of the product manufactured
by Mitsui Sekiyu Kagaku Co.)
(4) Acrylic type rubber ("PARALOID KM-330", registered trademark of the product manufactured
by Rohm and Haas Co.in U.S.A.)
(5) PIB-A ("VISTANEX-MML-140", registered trademark of the product manufactured by
Exson chemical Co. average molecular weight : about 12,500)
(6) PIB-B ("VISTANEX-MML-80", registered trademark of the product manufactured by
Exson chemical Co. average molecular weight : about 72,000)
(7) PIB-C ("ESSOBUTYL-#065", registered trademark of the product manufactured by Ecson
chemical Co. average molecular weight : about 350,000)
[0060] As the fibrous fillers, the followings were used.
(1) Glass fiber A (10 11m in diameter) ("CS03J-942CB", the product manufactured by
Nittobo Co.)
(2) Glass fiber B (6 11m in diameter) ("ECS03-T-717DE", the product manufactured by Nippon Denki Glass Co.).
[0061] For each of the samples of PIB, "IRGANOX #246" (registered trademark of the product
manufactured by Ciba Geigy as a stabilizer was added 2 phr and it was roll-kneaded
respectively to obtain a stabilized PIB.
[0062] Each of the modifiers was frozen and pulverized by using a mill and melt-kneaded
with the polymer A obtained in the Synthesis Experimental Example 1. Upon melt-kneading,
a predetermined amount of each of the modifiers was added to 100 parts by weight of
the polymer A. Further, 0.1 parts by weight of Ca(OH)
2, 0.1 parts by weight of N-phenyl-y-aminopropyl triethoxysilane and 66.7 parts by
weight of glass fiber A were added to 100 parts by weight of the composition (PATE
of polymer A + each of the modifiers), which were uniformly dry-blended by using a
Henschel mixer, supplied to a single-screwed kneading extruder, melt-kneaded at 310°C,
extruded into a strand-like form and then cut to obtain pellets of respective compositions.
[0063] Each of the pellets was injection molded at 290 - 320°C by using an injection molding
machine to obtain a test piece for the measurement of physical property.
[0064] For evaluating the toughness and the impact resistance for the obtained test pieces,
the maximum flexural distortion and izod impact strength were measured according to
the method of ASTM D-790 and the method of ASTM D-256 respectively. At the same time,
for evaluating the heat resistance, the heat distortion temperature (HDT) was measured
according to the method of ASTM D-648. The results are collectively shown in Table
1.
[0065] Further, photographs of the flactured cross section of the test pieces for the izot
impact strength of experimental code numbers 1,3,5 and 9 were taken by a scanning
type electron microscopic photography and after studying them it was found that polyisobutylene
was mainly existing at the surface of the glass fibers to improve the adhesion between
the fibers and PATE in the case of the molded product containing PATE, PIB and glass
fibers according to the present invention.
Example 2
[0066] 5 parts by weight of a stabilized PIB pulverizate prepared in Example 1 was added
to 100 parts by weight of the polymer B obtained in the Synthesis Experimental Example
2 and, further, 0.1 part by weight of Ca(OH)
2 and 25 parts by weight of glass fiber B were uniformly mixed with 100 parts by weight
of the composition (PATE of polymer B + PIB) by using a Henschel mixer, and the mixture
was supplied to twin-screwed kneading extruder and melt-kneaded at 310°C to obtain
molded product in a pellet farm. The pellet was supplied to an encapsulating injection
molding machine ("JT-40S", manufactured by Nihon Seikosho Co.) and subjected to encapsulation
molding by using an IC lead frame.
[0067] After dipping the obtained encapsulated molded product in an red ink at 150°C for
20 hours, the molded product was cut open to observe the degree of penetration of
the red ink to the inside of the encapsulated molded product. For the comparison,
the composition with no PIB addition was also subjected to encapsulation molding and
applied the red ink intrusion test.
[0068] As a result, some intrusion of the red ink was observed to the inside of the encapsulation
molded product obtained with the composition containing no PIB, while no substantial
intrusion of the red ink was observed to the inside of the product incorporated with
PIB.
Example 3
[0069] Injection molded products prepared according to the method of code numbers 1 and
5 of Example 1, provided that 3.0 parts by weight of CaC0
3 was added to 100 parts by weight of the polymer A only or (polymer A + PIB-B) composition,
were obtained.
[0070] The toughness, the impact resistance and the heat resistance of the molded products
of polymer A and (polymer A + PIB-B) composition were measured and the results are
as follows:

1. A polyarylene thioether composition comprising:
(A) 100 parts by weight of polyarylene thioether having the repeating unit

as the main constituent, and (B) from 0.3 to 70 parts by weight of polyisobutylene
having the repeating unit (̵ CH2-C(CH3)2)̵as the main constituent.
2. A composition according to claim 1, wherein ingredient (A) is a copolymer containing
from 60 to 95 molo/o of the repeating unit

and from 40 to 5 mol% of the repeating unit
3. A composition according to claim 2, wherein the copolymer is a block copolymer.
4. A composition according to any one of the preceding claims, wherein ingredient
(A) is a substantially linear polyarylene thioether containing not less than 75 mol%
of the repeating unit
5. A composition according to any one of the preceding claims, wherein ingredient
(B) is a polyisobutylene containing not less than 80 mol% of the repeating unit(̵CH2-C(CH3)2)̵.
6. A composition according to any one of the preceding claims, wherein ingredient
(B) is a polyisobutylene containing not more than 5 mol% of aliphatic double bonds.
7. A composition according to any one of the preceding claims, comprising (C) up to
400 parts by weight, per 100 parts by weight of (A) + (B), of a filler selected from
a fibrous filler, an inorganic powdery filler, a synthetic resin or an elastomer or
two or more thereof.
8. A composition according to claim 7, wherein said fibrous filler is selected from
glass fibers, carbon fibers, graphite fibers, silicon carbide fibers, silica fibers,
alumina fibers, zirconia fibers, potassium titanate fibers, calcium sulfate fibers,
calcium silicate fibers, aramide fibers, wollastonite as natural fibers and two or
more thereof.
9. A composition according to claim 7 or 8, wherein said inorganic powdery filler
is selected from talc, mica, kaolin, clay, diatomaceous earth, magnesium phosphate,
magnesium carbonate, calcium carbonate, calcium silicate, calcium sulfate, silicon
oxide, aluminum oxide, titanium oxide, chromium oxide, iron oxide, copper oxide, zinc
oxide, carbon, graphite, boron fluoride, molybdenum disulfide, silicon and two or
more thereof.
10. A composition according to any one of the preceding claims, which is in the form
of a molded product.
11. A process for the preparation of a composition as claimed in any one of the preceding
claims, which process comprises blending the ingredients in the desired proportions.